As more and more computers are interconnected through various networks, such as the Internet, computer security also becomes increasingly more important. In particular, computer security in regard to external attacks from malware has become, and continues to become, increasingly more important. Malware, for purposes of the present discussion, are defined as unwanted computer attacks. As such, those skilled in the art will appreciate that malware includes, but is not limited to, computer viruses, Trojan horses, worms, denial of service attacks, abuse/misuse of legitimate computer system functions, and the like. The primary defense against malware is anti-virus software.
FIGS. 1A and 1B are pictorial diagrams illustrating how anti-virus software currently operates. In particular, FIG. 1A illustrates how anti-virus software detects known malware, and prevents the known malware from reaching and infecting a computer. Alternatively, FIG. 1B illustrates a common weakness of anti-virus software, particularly, how anti-virus software is unable to detect and prevent modified malware from reaching and infecting the computer. What is meant by “reaching” the computer is getting past the anti-virus software. Those skilled in the art will readily recognize anti-virus software almost always resides on the computer it is protecting, and operates on incoming data as it physically arrives at the computer. Thus, while incoming data, including malware, may be located at the computer, for purposes of the present invention, the incoming data does not actually “reach” the computer until it gets past the anti-virus software.
As shown in FIG. 1A, a malware 102 is directed over a network 106 to the computer 110, as indicated by arrow 108. It will be appreciated that the malware 102 may be directed to the computer 110 as a result of a request initiated by the computer, or directed to the computer from another network device. However, as mentioned above, before the known malware 102 reaches the computer 110, anti-virus software 104 installed on the computer intercepts the malware and examines it. As is known in the art, currently, anti-virus software scans the incoming data as a file, searching for identifiable patterns, also referred to as signatures, associated with known-malware. If a malware signature is located in the file, the anti-virus software 104 takes appropriate action, such as deleting the known malware/infected file, or removing the malware from an infected file, sometimes referred to as cleaning the file. In this manner, anti-virus software 104 is able to prevent the known malware 102 from infecting the computer 110, as indicated by the arrow 112.
Those skilled in the art will appreciate that almost all unknown malware are actually rewrites or reorganizations of previously released malware. Indeed, encountering an absolutely novel malware is relatively rare, as most “new” malware are actually rewrites or rehashes of existing malware. Malware source code is readily available, and it is a simple task for a malicious party to change variable names, reorder lines of code, or somehow superficially modify the malware.
The result of rehashing or rewriting an existing malware is that the static appearance of the malware is altered, though the functionality of the malware remains the same. Unfortunately, current anti-virus software operates only on known malware. Thus “new” malware, while functionally identical to its original/parent malware, is not detectable or stopped by the installed anti-virus software 104, due to its pattern matching system.
FIG. 1B is a pictorial diagram illustrating how current anti-virus software is unable to prevent a modified malware from reaching a computer. As shown in FIG. 1B, known malware 102 undergoes a modification process 114, such as a rehash or rewrite, resulting in modified malware 116. As mentioned above, the modified malware 116 will most likely have a different static appearance, though its functionality may be identical. As mentioned above, because the static appearance is modified, the modified malware 116 is not “known” malware recognized by the anti-virus software 104.
The modified malware 116 is directed through the network 106 to the computer 110, as indicated by arrow 118. As described above, the anti-virus software 104 attempts to identify the modified malware 116 to determine whether it is known malware and should be stopped. As the modified malware 116 is, as yet, an unknown modification, and because the signature of the modified malware is not the same as the original malware 102, the anti-virus software 104 fails to identify the modified malware as malware, and permits it to proceed to the computer 110, as indicated by arrow 120. Upon reaching the computer 110, the modified malware 116 may be able to perform its destructive purpose. It is only after an anti-virus software provider identifies a signature pattern for the modified malware 116, and then updates the anti-virus software 104, can the anti-virus software protect the computer 110 from the modified malware 116.
Constantly evaluating unknown malware to determine a static signature and then updating anti-virus software with that signature is a costly process. It is also inefficient, especially when considering that most malware are only superficially modified from other, known malware. Thus, it would be beneficial if malware could be identified, not just by its static signature, but rather by its exhibited behaviors. However, the only way to currently evaluate the exhibited behavior of malware is to somehow permit it to execute on a computer 110. Of course, this would be entirely unacceptable as the malware would perform its ill-intended effects on the computer 110 during its execution.
In light of the above-identified problems, it would be beneficial to computer users, both in terms of computer security and in terms of cost effectiveness, to have a malware detection system that operates in addition to, or separately from, current anti-virus software that protects a computer against rewritten or reorganized malware. This system should be able to detect malware according to its dynamic, exhibited behaviors, and not according to its static file organization. The present invention addresses this and other issues found in the prior art.